The present invention relates broadly to actuator apparatus, and in particular to an electromagnetic actuator driver apparatus.
The state of the art of control actuator apparatus is well represented and alleviated to some degree by the prior art apparatus and approaches which are contained in the following U.S. Patents:
U.S. Pat. No. 4,655,560 issued to Glomb, Jr. on Apr. 7, 1987;
U.S. Pat. No. 4,655,563 issued to Plante et al on Apr. 7, 1987; and
U.S. Pat. No. 4,717,873 issued to Carr, Jr. et al on Jan. 5, 1988.
The Glomb, Jr. patent describes a demagnetization compensated deformable magnetostrictive mirror comprising an array of magnetostrictive actuators that are positioned between a continuous low magnetic reluctance yoke. A faceplate having a reflective surface and a substrate are both fabricated to receive the magnetic yoke's outer surface and are affixed thereto to be approximately perpendicular to the mirror's deformation axis.
The Plante et al patent discusses a lightweight deformable mirror suitable for space applications in which a plurality of electrically-operated electrodistortive actuators may be used to selectively deform the mirror's reflecting surface. The actuators are sandwiched between a pair of thin sheets of glass with the surface of one sheet finished to form the mirrors reflecting surface.
The Carr Jr. et al patent discloses a magnetic displacement transducer system having a magnet that is movable in a tube whose interior is exposed to a fluid and having at least one magnetometer outside the tube.
In the prior art, mirrors with deformable surfaces are well known in the art, and have found extensive use in advanced high energy laser systems. The coherent light from a laser has surfaces of instant phase which are distorted while propagating through the atmosphere. In addition to reflecting the beam, the deformable mirrors provide a correction for this environmentally generated wavefront distortion. Deformable mirrors are characterized by a reflective surface behind which is positioned an array of externally controllable piezoelectric or magnetostrictive actuators. Upon receipt of an external signal, the actuators will exert a force upon the reflective surface and deform the originally planar surface into a surface whose geometry will provide the reflected wave with coherent phase.
The present invention is directed to an electromagnetic actuator driver apparatus which advances the art of deformable mirrors and which overcomes the problems and limitation of such prior art devices.